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'00 RS / V5 STI
624 Posts
Discussion Starter · #1 ·
Hey all,

I've got a EJ207 V6 converted to OBDII and passed the CA BAR as a 2003 WRX. It currently has a VF28, ID725cc injectors, and a tune from Delicious Tuning.

[Issue] - When at idle, I'll see AF Correction 1 peg at -25, and AFR peg at 11.25. After ~45 seconds of idling, it throws a P0172 code.

[Notes] - The FPR is new-ish (couple of years old at most), all vacuum lines are brand new, fresh rubber on the intake side across the whole system, , I'm not seeing any boost leaks (still hitting 20psi at WOT and lower intake temps), and it's able to idle OK minus the rich condition.

[Thoughts] - When doing my 6-speed swap, I think I re-used the turbo to downpipe gasket. This could be introducing more air, upstream from the rear O2 sensor. I seem to recall this possibly being an issue and causing this condition (rear O2 reads lean, adjusts AFRs to run richer, front O2 reads rich AFR, rinse and repeat).

Any other ideas? I'm happy to swap out that gasket and continue testing, and it's probably worth replacing the BPV gasket, but it seems this specific condition is all over the place on Nasioc and much of it doesn't apply to my car specifically.

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